Phosphorus is not adequately removed by dialysis, and must be controlled by a combination of dietary restriction and intake of phosphate binders. Hyperphosphatemia is common in hemodialysis patients and appears to be a key contributing factor to cardiovascular morbidity and mortality in this population. The purpose of this 2-phase study is to provide proof of concept and describe feasibility and acceptability of a behavioral intervention to engage hemodialysis patients in multiple behavior changes to properly manage hyperphosphatemia, including adherence to phosphate binders and reduction of dietary phosphorus while assuring adequate protein intake. In Phase 1, participants will be randomized, using equal allocation, to one of three 12-week programs: (Group 1) education alone, (Group 2) education plus mobile device dietary self- monitoring and feedback; or (Group 3) education plus mobile device dietary self-monitoring and feedback combined with Social Cognitive Theory-based counseling. Phase 2 will be an observation phase with no further intervention contact, although participants in Groups 2 and 3 are permitted to retain the technology and encouraged to continue self-monitoring. We will compare the study arms, primarily, in terms of behavior changes (adherence to binders and dietary intake), serum phosphorus, and normalized protein catabolic rate. We will describe the mediating effect of self-efficacy.